Fix quick actions don’t work on long traces in master broken incidents

What does this MR do and why?

This fixes a regression from showing job traces in collapsible sections (introduced in !2910 (merged)) in master broken incidents.

See gitlab-org/quality/engineering-productivity/master-broken-incidents#7101 (closed) as an example where it happene.d.

The problem is that quick actions don’t need to have a space between the markdown content, unless the content is a HTML element, so this MR adds an extra space after the collapsible section element:

Content	Preview
hello /label ~backend	hello Applies backend label
<p>hello</p> /label ~backend	hello /label backend
<p>hello</p> /label ~backend	hello Applies backend label

You can try this out in any comment box to test the fix.

Expected impact & dry-runs

All master broken incidents with job traces over 30 lines.

Action items

• If adding environment variables for reactive processors, update config/triage-web.yaml and .gitlab/ci/triage-web.yml
• (If applicable) Add documentation to the handbook pages for Triage Operations =>
• (If applicable) Identify the affected groups and how to communicate to them:
  • /cc @person_or_group =>
  • Relevant Slack channels =>
  • Engineering week-in-review